Snapper ST1842 Deck Height Adjustment Problem

I just bought a Snapper ST1842 from Wal-Mart and proceeded to cut my lawn discovering that with the deck height set at 6 (highest level), it scalped my yard. I went ahead and measured the deck height and found that at level 6 it was 2 3/4 inches off the floor. I couldn't even lower the deck to level 1 because it bottoms out at level 2. I checked the specs online and the deck should adjust between 1 and 4 inches. Does anybody know whether there is a way I can adjust the mower height? Any suggestions or comments are appreciated. Thanks, John